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just for Sean ONeil

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Bob Zelin
just for Sean ONeil
on Dec 10, 2008 at 6:37:42 pm

Sean writes -

Another thing. If you aggregate 4 ports, you don't exactly get a single 4gbps port as you suggested. Instead you get up to 4 sessions at 1gbps max each. In other words, say you use Link Aggregation on a Mac client and link 4 ports together. Then connect to a server that also has 4 linked ports. Your max bandwidth for a single video stream is still only 1gbps.

Just wanted to clear that up. When I first heard of Link Aggregation, I too thought it was the same a having a 4gb ethernet connection


REPLY -
Link aggregation, or IEEE 802.3ad or IEEE 802.1AX-2008, is a computer networking term which describes using multiple network cables/ports in parallel to increase the link speed beyond the limits of any one single cable or port, and to increase the redundancy for higher availability.


Link aggregation is an inexpensive way to set up a high-speed backbone network that transfers much more data than any one single port or device can deliver.

Trunking is not just for the core switching equipment. Network Interface Cards (NICs) can also sometimes be trunked together to form network links beyond the speed of any one single NIC. For example, this allows a central file server to establish a 2-gigabit connection using two 1-gigabit NICs trunked together.

more information -
Using multiple transmission paths between network devices in order to increase transmission speed. Port aggregation between a server and a switch requires multiple network adapters (NICs) in the server or adapters with multiple ports. Each server port hooks up to a switch port, and the port aggregation software is typically in the server. When port aggregation is provided between switches, the software is in the switches. Also called "link aggregation," "trunking" and "multilink trunking."

A quote from the DELL site -
Link aggregation addresses all these problems by providing higher capacity and availability with little or
no additional hardware

Bob Zelin




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Bob Zelin
Re: just for Sean ONeil (more good info)
on Dec 10, 2008 at 6:43:09 pm

Hi Sean -
you do NOT want to spend a penny on new storage, or a new computer- you have plenty of MAC G5 PCI-X computers.

Well, if you have a PCI-X G5 just sitting there, with PCI-X interface cards for your exsiting storage - WHY NOT BUY THIS SMALL
TREE PRODUCT -

http://www.small-tree.com/Quad_Port_Copper_PCI_X_Gigabit_Ethernet_Server_p/...

This is the PXG4. It's a PCI-X 4 port ethernet card that costs $669 dollars. Combine this with a Netgear 724T switch for $259 at PC Connection (if you can figure out how to configure the link aggregation on the Netgear), and you are in business WITH YOUR OLD G5 and OLD STORAGE.

Is this an acceptable answer for you, or is it STILL TOO EXPENSIVE?

Bob Zelin




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Matt Geier
Re: just for Sean ONeil (more good info)
on Dec 10, 2008 at 8:35:16 pm

Sean,

I know you're looking for the most inexpensive way to get a "shared storage" environment going....

I'm also going to pipe in here and give you a heads up to be very careful in deciding to purchase an "Smart" switch. Here's the reason why;

Apple systems will only support Dynamic Link Aggregation. This switch that Mr. Zelin called out is a Netgear 724T and is equivalent to Small Tree's ES4324 WEB SMART switch. Neither of which will support Dynamic Link Aggregation. These switches, both of them, along with every other Web Smart switch, do support 802.3AD which is the IEEE call for LACP (Link Aggregation), however that specifically refers to Static Link Aggregation by default. Dynamic Link Aggregation is also part of the 802.3AD support, however, not on the Web Smart Switches. I've done extensive research on Web Smart switches, and ALL of them contain no Dynamic Link Aggregation support.

Another situation you'll run into in purchasing a switch that's less then a Managed Gigabit Switch is the fact that there are no hardware ASIC's inside of them. It's very common for someone to purchase a switch like this and have problems out of the gate because as they hit and pound the switch, it degrades in performance because there's no processing power in it with fans and all that jazz.

The bottom line is that, especially with an Apple, you're going to have to invest in a Managed Gigabit Switch. (1K-5K depending on the Brand/Vendor)

Small Tree certainly has a ES4524D / 48D. Which would be equivalent to many others on the Gigabit Managed Switch market.


Just my 0.02 with regard to this ...






Matt G.


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Sean ONeil
Re: just for Sean ONeil (more good info)
on Dec 11, 2008 at 5:25:56 am

Matt,

Thanks for the info, but I think there's some confusion. I already have a managed Dell Powerconnect that supports dynamic LACP. In fact I think one of you guys recommended it to me back in 2005 when I purchased several dual-port Broadcom cards from you guys.

Bob,

Loved your article. I mean no disrespect, I just think it's important those who read your article know that they do not need an expensive managed switch if they have 4 edit stations or less. That's the only reason I commented. I actually obtained this information from Small Tree. Copied and pasted form a June 1, 2008 email from Steve Modica:

"Link agg is only useful in over subscribed situations. If you have 3 systems and 3 ports, don't use it. If you have 6 systems and 3 ports, then it starts to make sense."



Sean


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Sean ONeil
Re: just for Sean ONeil (more good info)
on Dec 11, 2008 at 5:20:51 am

[Bob Zelin] "Well, if you have a PCI-X G5 just sitting there, with PCI-X interface cards for your exsiting storage - WHY NOT BUY THIS SMALL
TREE PRODUCT -"


Because I already have three of them :).

Sean


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Sean ONeil
Re: just for Sean ONeil
on Dec 11, 2008 at 5:19:06 am

[Bob Zelin] "Another thing. If you aggregate 4 ports, you don't exactly get a single 4gbps port as you suggested. Instead you get up to 4 sessions at 1gbps max each. In other words, say you use Link Aggregation on a Mac client and link 4 ports together. Then connect to a server that also has 4 linked ports. Your max bandwidth for a single video stream is still only 1gbps.

Just wanted to clear that up. When I first heard of Link Aggregation, I too thought it was the same a having a 4gb ethernet connection


REPLY -
Link aggregation, or IEEE 802.3ad or IEEE 802.1AX-2008, is a computer networking term which describes using multiple network cables/ports in parallel to increase the link speed beyond the limits of any one single cable or port, and to increase the redundancy for higher availability.


Link aggregation is an inexpensive way to set up a high-speed backbone network that transfers much more data than any one single port or device can deliver.

Trunking is not just for the core switching equipment. Network Interface Cards (NICs) can also sometimes be trunked together to form network links beyond the speed of any one single NIC. For example, this allows a central file server to establish a 2-gigabit connection using two 1-gigabit NICs trunked together.

more information -
Using multiple transmission paths between network devices in order to increase transmission speed. Port aggregation between a server and a switch requires multiple network adapters (NICs) in the server or adapters with multiple ports. Each server port hooks up to a switch port, and the port aggregation software is typically in the server. When port aggregation is provided between switches, the software is in the switches. Also called "link aggregation," "trunking" and "multilink trunking.""


802.3ad LACP on Apple OS X does fault tolerance and load balancing, not round robin (which is what you are describing). Extra bandwidth can be achieved by using multiple sessions. However, a stream of video is not segmented into multiple sessions. So you get 1gbps max in the case of editing video. Uncompressed 1080 is impossible.

Sean


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Bob Zelin
Re: just for Sean ONeil (impossible ?)
on Dec 12, 2008 at 2:53:31 am

Sean writes -
802.3ad LACP on Apple OS X does fault tolerance and load balancing, not round robin (which is what you are describing). Extra bandwidth can be achieved by using multiple sessions. However, a stream of video is not segmented into multiple sessions. So you get 1gbps max in the case of editing video. Uncompressed 1080 is impossible.

Sean

REPLY - uncompressed 1080 is impossible with Gigabit ethernet, because the maximum bandwidth is 70Mb/sec even with jumbo frames enabled. HOWEVER, uncompressed video is VERY do-able with 10Gb ethernet (available from Small Tree and others), because 10Gb ethernet allows for 180Mb/sec, and uncompressed 1080i only requires
118.7 Mb.sec for 8 bit uncomrpessed, and 157.2Mb/sec for uncompressed 10bit 1080i.

These limitations are based on Apple AFP. There are other alternative solutions as well, that offer more bandwidth that DO NOT use Fibre channel. One such solution is AoE (ATA over ethernet) - I am just learning about this - and became aware of this on THIS VERY FORUM from Robin Frost at 2 Degrees Frost, who makes a codec for MAC platform that supports AoE. I now understand that Small Tree as well has an AoE codec, that will ALLEGEDLY allow 200Mb/sec over ethernet, but don't quote me here, because this is here-say, and I know nothing about this stuff YET.

Bob Zelin





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Sean ONeil
Re: just for Sean ONeil (impossible ?)
on Dec 12, 2008 at 3:30:44 am

[Bob Zelin] "HOWEVER, uncompressed video is VERY do-able with 10Gb ethernet"

Of course.

[Bob Zelin] "because the maximum bandwidth is 70Mb/sec even with jumbo frames enabled"

Right, but I was talking about trunking 4 ports together. Not just on the server end, but the client end as well (4-port Small Tree card in the Mac workstation). It's still 70MB/s (or whatever max you'd get if you only used 1 gb port).

[Bob Zelin] "These limitations are based on Apple AFP."
I don't think AFP is the problem. You can get "wire speed" (1gbps) with AFP. There are lot't of factors preventing it and causing you to get 70mbps, but it's not AFP. On the same system, try SMB sharing, NFS sharing, or try testing an FTP server and client. AFP will probably be faster than those when going from Mac to Mac.

When they told you AFP was the problem, I think that was their way of saying this:

File-level sharing (AFP, SMB, NFS, etc.) and block-level sharing (iSCSI, AoE, Fibre Channel) are two completely different things. Block-level is typical going to be faster for editing. The problem is that you can only have one client at a time since it essentially works just like direct-attached storage. Multiple clients will cause data corruption unless a special cluster file system is used. Hence the need for SAN software (Xsan, MetaSAN, SANmp, etc.). Block-level storage combined with this software is what makes something a SAN. But with AFP, for example, it's not a SAN, rather it's called a NAS. So while you don't get block-level performance, you don't need any special software either.


[Bob Zelin] "One such solution is AoE (ATA over ethernet) - I am just learning about this - and became aware of this on THIS VERY FORUM from Robin Frost at 2 Degrees Frost, who makes a codec for MAC platform that supports AoE."

See my experience with this:
http://forums.creativecow.net/readpost/197/855207

Sean


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Bob Zelin
Re: just for Sean ONeil (impossible ?)
on Dec 12, 2008 at 10:01:36 pm

I read your post on 2 Degrees Frost (and everyone elses comments).

In all of this confusion, and discussion, I am embarassed to say that I have NO IDEA of what you are trying to accomplish at this point. How many FCP and graphics systems are you trying to connect for shared media ?

Bob Zelin




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Sean ONeil
Re: just for Sean ONeil (impossible ?)
on Dec 13, 2008 at 3:14:58 am

All I'm trying to do is make the most out of the hardware I already have. There are 3 editors, possibly 5 in the near future.

In regards to the topic I started, I'm about to give FreeNAS another go since there have been new versions of it, and I was curious if anyone else had tried it. If it doesn't work out I'll consider turning a G5 into a server and share it over AFP, as you've suggested.


Sean


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Bob Zelin
Re: just for Sean ONeil (impossible ?)
on Dec 13, 2008 at 2:47:55 pm

I re read both entire posts. I am getting the impression (and I could be wrong, because I mis read things often), that you feel that FreeNas directly affected the performance of the network you set up (you could not get ProRes to playback). When you observed this - did you check to see if your data transfer rate was different without Freenas installed ?

Bob Zelin




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Sean ONeil
Re: just for Sean ONeil (impossible ?)
on Dec 14, 2008 at 2:04:57 am

Bob,

FreeNAS is not an application you run on your Mac. It is an operating system specifically designed to turn a computer into a storage appliance. Instead of using a Macintosh computer to serve the storage, you instead use a server-grade PC with SATA disks attached and FreeNAS running as the system disk. But rather than using a hard drive as the system disk, FreeNAS is so small you can install it on a USB thumb drive. FreeNAS could run on an Intel Mac using Boot Camp, but that would of course defeat the purpose.

Once the FreeNAS server is set up, you connect to it using AFP on your Macintosh workstation. Just like you would connect to another Mac.

Yes, FreeNAS was the reason AFP performance was weak. However, just today I tried the latest alpha version and AFP performance was pretty good. AJA System Test showed 70MB/s write, 100MB/s read. Before it was something like 20MB/s. But since it's an alpha I'm not about to deploy it. Something to try again in the future.



Sean


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Bob Zelin
Re: just for Sean ONeil (impossible ?)
on Dec 14, 2008 at 6:21:18 pm

From my ignorance of this product,and VMWare, I guess I just find it hard to believe (and incredible) that a 32Meg program runs the server, the display, the disk drive host card, and manages the distribution of the storage to multiple clients. If this is a stand alone operating system, how does it know how to run the native host controller on the server PC. Do you assign the clients and their IP's
in Freenas ?

Bob Zelin




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Sean ONeil
Re: just for Sean ONeil (impossible ?)
on Dec 14, 2008 at 8:06:09 pm

It's a stripped-down version of FreeBSD (which is what OSX is loosely based on). There is no graphic desktop environment. That's why it's so small. No icons, no wallpaper, no web browser, no apps whatsoever. The machine itself gives you a simple text menu to set the IP addresses and such. Then you connect to it over the network and there is a web-based graphic interface to control it all. Here's a screenshot of the Web interface:
http://www.dailycupoftech.com/wp-content/uploads/2006/11/freenas13.png

Sean


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Sean ONeil
AFP Sharing
on Dec 14, 2008 at 8:25:33 pm

There's a lot of options. Not sure what I'm going to do. Using a G5 does look more promising than in the recent past. I see all the new SATA cards support port multipliers, which is interesting. And I just found is that ZFS is unofficially available on the current Leopard. Apple provides the source code and there is a community that builds installers for it.
http://zfs.macosforge.org/trac/wiki

Then there's the whole Time Machine thing. I'm thinking of turning a FreeNAS server into a giant Time Machine disk for backing up media. Lots to think about.




Sean


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